1. Field of the Invention
The present invention relates to a thermosensitive recording medium which utilizes a coloring reaction between an electron-donating coloring compound and an electron-accepting compound, more particularly to a transparent thermosensitive recording medium which utilizes the above-mentioned coloring reaction, which can be used as an image formation film sheet for overhead projectors (hereinafter referred to as OHP) and for CAD.
2. Discussion of Background
Thermosensitive recording media which utilize a coloring reaction between an electron-donating coloring compound (hereinafter referred to as a coloring agent) and an electron-accepting compound (hereinafter referred to as a color developer) are widely known and used.
In recent years, there is a demand for a thermosensitive recording medium for use in a large size overhead projector and for use as a second original for diazo copying, and for preparing design drawings.
Transparent thermosensitive recording media on which recording can be directly made thereon by a thermal head have been proposed in Japanese Patent Application 61-121875 and Japanese Laid-Open Patent Application 1-99873.
These transparent thermosensitive recording media have the shortcomings that for the production thereof, there are required complicated steps such as microcapsulizing a coloring agent, coating a transparent support with an emulsion dispersion which is prepared by emulsifying a color developer in an organic solvent which is insoluble or slightly soluble in water, and that the transparency of the recording media is not sufficient for use in practice.